Modular impaction grafting tamps

ABSTRACT

Methods for impaction grafting an intramedullary canal of a bone including a first canal portion and a second canal portion spaced along a canal axis. A first tamp may be moved axially within the canal to impaction graft the first canal portion. A second tamp may be mounted to the first tamp in axial sliding relationship and moved axially within the canal relative to the first tamp to impaction graft the second canal portion. The first and second tamps may be locked together in fixed axial relationship to prevent relative axial movement between the first tamp and the second tamp while the first tamp is moved to impaction graft the first canal portion before impaction grafting the first canal portion. The first and second tamps may be unlocked to permit relative axial sliding of the first and second tamps before impaction grafting the second canal portion.

FIELD OF THE INVENTION

The present invention relates generally to the field of orthopaedics,and, more particularly, to impaction grafting tamps.

BACKGROUND¹

Arthroplasty is surgery to relieve pain and restore range of motion byrealigning or reconstructing a joint. Typical arthroplastic optionsinclude joint resection, interpositional reconstruction, and total jointreplacement. Joint resection involves removing a portion of a bone froma joint to create a gap between the bone and the corresponding socket,thereby improving the range of motion. Scar tissue eventually fills thegap. Pain may be relieved and motion restored, but the joint istypically less stable. Interpositional reconstruction reshapes the jointand adds a prosthetic disk between the bones forming the joint. Theprosthesis can be made of plastic and metal or from body tissue such asfascia and skin. If the joint does not respond to the more conservativetreatments (which may include medication, weight loss, activityrestriction, and/or use of walking aids such as a cane), jointreplacement is often considered appropriate. Joint replacement (i.e.,total joint arthroplasty) is the surgical replacement of a joint with aprosthesis. Many joint replacements are needed because arthritis hascaused the joint to stiffen and become painful to the point where normaldaily activities are no longer possible. Arthroplasty, especially jointreplacement, is becoming an increasingly prevalent treatment. Forexample, it has been reported that more than 170,000 hip replacementsand more than 200,000 knee replacements are performed in the UnitedStates each year. ¹ See Gale Encyclopedia of Medicine, Gale Research(1999), found athttp://www.findarticles.com/cf_dls/g2601/0007/2601/000783/p1/article.jhtml?term=.

A conventional hip prosthesis includes an artificial socket and afemoral stem. The artificial socket is typically made of metal coatedand polyethylene (a plastic) to reduce friction. The femoral stem has aball at one end and an elongated post or spike at the other. In arelatively simple hip replacement operation, the surgeon makes anincision in the area of the distal femur and then pulls the distal femuraway from the acetabulum (socket of the hip bone). Next, the surgeoninserts the artificial socket into the acetabulum. The surgeon cuts andshapes the distal femur, inserts the post of the femoral stem into themedullary canal of the distal femur, and fits the ball of the stem intothe artificial socket. The surgeon secures the artificial socket and thepost of the stem within the acetabulum and the medullary canal,respectively, with an acrylic polymer (a synthetic cement).Alternatively, the artificial socket and the post may be designed forfixation by natural bone in-growth.

However, not all hip replacements are so simple. Impaction grafting isincreasingly incorporated in cases that are complicated by substantialbone loss within the femur. Impaction grafting is a technique in whichthe surgeon uses impaction grafting tamps to impact morselized allograft(a replacement material typically made from bone chips, among otherthings) into the medullary canal of the femur. The allograft creates anew canal for receiving the femoral stem.

Conventional impaction grafting approaches include progressivelyimpacting the subject bone cavity with allograft to ensure a highoverall finished graft integrity. But properly aligning and otherwisemanipulating the differently sized and shaped tamps needed forprogressive impaction grafting has been challenging.

SUMMARY OF THE INVENTION

The present invention provides an apparatus including a plurality ofseparable impaction grafting tamps coupled to form an integratedimpaction grafting tamp.

In an alternative embodiment, the present invention provides anapparatus including a first impaction grafting tamp defining a firstchannel including a sleeve portion. The apparatus further includes anelongated member including an elongated first portion and an elongatedsecond portion together defining a second channel. The first portion ofthe elongated member is positioned in the sleeve portion of the firstchannel, and the first channel communicates with the second channel toform an integrated channel including a first opening and a secondopening axially spaced apart from the first opening.

In another alternative embodiment, the present invention provides anapparatus for impaction grafting a canal including a first portion and asecond portion. The apparatus includes a first means for impactiongrafting the first portion of the canal, and further includes a secondmeans, removably coupled to the first means, for impaction grafting thesecond portion of the canal.

The above-noted features and advantages of the present invention, aswell as additional features and advantages, will be readily apparent tothose skilled in the art upon reference to the following detaileddescription and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an anterior plan view of an exemplary apparatus accordingto the present invention;

FIG. 2 shows a medial plan view of the exemplary apparatus;

FIG. 3 shows a lateral plan view of the exemplary apparatus;

FIG. 4 shows an exploded cross-sectional view of the exemplary apparatus(without the guide rod), along line 5-5 of FIG. 2;

FIG. 5 shows an assembled cross-sectional view of the exemplaryapparatus (without the guide rod), along line 5-5 of FIG. 2;

FIG. 6 a, FIG. 6 b, FIG. 6 c, and FIG. 6 d show anterior plan views ofthe guide rod, the connecting screw, a connecting handle, and anextension member, respectively; and

FIG. 7 a, FIG. 7 b, FIG. 7 c, and FIG. 7 d show cross-sectional views ofthe guide rod, connecting screw, connecting handle, and extensionmember, respectively, along lines 7 a-7 a, 7 b-7 b, 7 c-7 c, and 7 d-7 dof FIG. 6 a, FIG. 6 b, FIG. 6 c, and FIG. 6 d, respectively.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

Although various views of the drawings may be identified herein as“anterior plan,” “medial plan,” “lateral plan,” and the like, it isnoted that these view designations are merely for clarity of expositionand, accordingly, they do not indicate limitations of the presentinvention.

FIG. 1 shows an anterior plan view of an exemplary apparatus 200according to the present invention. The various components of exemplaryapparatus 200 described herein are made from stainless steel, plastic,or any other material suitable for use in surgical procedures, and theyare of suitable size and weight for manipulation by hand. Additionally,the components of exemplary apparatus 200 are reusable, and accordingly,are made suitable for sterilization in an autoclave. Referring to FIG.1, exemplary apparatus 200 includes an impaction grafting tamp 210. Tamp210 includes an outer, tamping surface 220 and further includes anotched post 230. Next to post 230, tamp 210 also includes an inwardlyextending generally cylindrical bore 234 (see FIG. 2, FIG. 4, and FIG.5). In general, surface 220 is tapered and otherwise suitably shaped fortamping allograft into a proximal portion of a distal femur.

Apparatus 200 further includes an impaction grafting tamp 240. Tamp 240includes an outer, tamping surface 250 that is narrowly spaced apartfrom surface 220 by a small (approximately 0.010 inches wide) gap 260.In general, surface 250 is tapered and otherwise suitably shaped fortamping allograft into a distal portion of the distal femur. Gap 260 islarge enough to prevent the edges of surface 220 and surface 250 fromwearing on each other, yet gap 260 is small enough to prevent allograftfrom becoming trapped between the tamp 210 and tamp 240 duringoperation. It should be appreciated, then, that surface 220 and surface250 together form a generally tapered, practically continuous tampingsurface. In alternative embodiments, surface 220 and/or surface 250 mayinclude any suitable additional tapering or even overlapping at gap 260to otherwise inhibit entrapment of allograft between tamp 210 and tamp240. It is reiterated, however, that apparatus 200 is merely exemplary.In alternative embodiments tamp 210 and/or tamp 240 may be replaced byone or more other suitably sized and shaped impaction grafting tamps forimpaction grafting a distal femur or any other bone cavity.

Further, apparatus 200 includes a connecting screw 270 and a cylindricalsmooth guide rod 280. Rod 280 has a diameter or width 284. As discussedin further detail below, screw 270 holds tamp 210 together with tamp240, and rod 280 extends through screw 270 and tamp 240.

FIG. 2 shows a medial plan view of exemplary apparatus 200. Bore 234 andadditional portions of surface 220 and surface 250, among other things,are discernable in FIG. 2. Meanwhile, FIG. 3 shows a lateral plan viewof exemplary apparatus 200. Yet additional portions of surface 220 andsurface 250, among other things, are discernable in FIG. 3.

FIG. 4 shows an exploded cross-sectional view of exemplary apparatus 200(without guide rod 280), along line 5-5 of FIG. 2. As discernable inFIG. 4, tamp 210 defines an elongated channel 300. Channel 300 includesan end opening 310 and an elongated cylindrical smooth end portion 320extending inwardly from opening 310. Further, channel 300 includes anend opening 330 and an elongated smooth portion 340 extending inwardlyfrom opening 330. Transverse to the elongation of channel 300, portion340 has a rectangular, elliptical, or any otherwise noncircularcross-sectional shape. In alternative embodiments, portion 340 may becylindrical. Additionally, channel 300 includes a cylindrical smoothintermediate portion 350 extending between portion 320 and portion 340.The diameter or width of portion 320 (transverse to the elongation ofchannel 300) is greater than the diameter or width (transverse to theelongation of channel 300) of portion 350; the width of portion 340(transverse to the elongation of channel 300) is greater than thediameter or width (transverse to the elongation of channel 300) ofportion 320; and the width of portion 340 (transverse to the elongationof channel 300) is greater than the diameter or width (transverse to theelongation of channel 300) of portion 350. Channel 300 also includes agenerally planar surface 354 rimming portion 350 and extending radiallyto portion 340.

Tamp 240 includes an elongated portion 360 and an elongated portion 370that together define an elongated channel 380. Portion 360 has atransverse cross-sectional shape (transverse to the elongation ofchannel 380) that is about the same as, but slightly smaller than, thatof portion 340 of channel 300. It should be appreciated, then, thatportion 300 forms a sleeve that receives portion 360. Thus, in theexemplary embodiment portion 360 slidably (but not rotationally) engagesthe inside of portion 340; whereas, in alternative embodiments in whichportion 340 and portion 360 are cylindrical, portion 360 slidably androtationally engages the inside of portion 340.

Channel 380 includes an end opening 390 and an elongated smoothcylindrical portion 400 extending inwardly from opening 390. Channel 380also includes a threaded cylindrical portion 410 and an end opening 420.Portion 410 extends between portion 400 and opening 420. The diameter orwidth of portion 410 (transverse to the elongation of channel 380) isslightly less than that of portion 350 of channel 300, while thediameter or width of portion 400 (transverse to the elongation ofchannel 380) is less than that of portion 410. Additionally, thediameter or width of portion 400 is slightly greater than diameter orwidth 284 of rod 280 such that rod 280 (see FIG. 1) slidably androtationally engages the inside of portion 400. Portion 360 alsoincludes a generally planar surface 424 rimming portion 410 and opening420.

Screw 270 includes a cylindrical head 430 having a diameter or widthabout the same as that of portion 320 of channel 300. Head 430 has atextured outer surface or any other outer surface suitable for grippingand manipulating screw 270 by hand. Screw 270 further includes athreaded shaft 440 having a diameter or width slightly less than that ofportion 350 of channel 300. The diameter and threading of shaft 440corresponds to that of portion 410 of channel 380 such that shaft 440screws into portion 410 and, thus, screw 270 holds tamp 210 togetherwith tamp 240. Additionally, screw 270 defines a cylindrical channel 450having a diameter or width about the same as that of portion 400 ofchannel 380, such that rod 280 (see FIG. 1) also slidably androtationally engages the inside of channel 450.

FIG. 5 shows an assembled cross-sectional view of exemplary apparatus200 (without guide rod 280), along line 5-5 of FIG. 2. When fullyassembled, portion 360 of tamp 240 is inserted into portion 340 ofchannel 300 (of tamp 210) such that surface 354 of tamp 210 meetssurface 424 of tamp 240 (see FIG. 4). Further, portion 350 of channel300 communicates with portion 410 of channel 380 (see also FIG. 4) suchthat channel 300 and channel 380 form an integrated channel thatreceives screw 270 at one end and includes opening 390 at another end.It should be appreciated that this integrated channel is defined byportion 320 of channel 300 (see FIG. 4), portion 350 of channel 300,portion 410 of channel 380, and portion 400 of channel 380.Additionally, it should be appreciated that channel 450 of screw 270also communicates with portion 400 of channel 380 to form an integratedchannel that is coaxial with the integrated channel defined by portion320, portion 350, portion 410, and portion 400. As discussed above (seeFIG. 1), tamping surface 220 remains narrowly spaced apart from tampingsurface 250 by gap 260, yet the two tamps together provide a practicallycontinuous tamping surface. Thus, it should be appreciated that whenassembled tamp 210 and tamp 240 together form an aligned, integratedoverall impaction grafting tamp.

FIG. 6 a, FIG. 6 b, FIG. 6 c, and FIG. 6 d show anterior plan views ofguide rod 280, connecting screw 270, a connecting handle 460, and anextension member 470, respectively. In alternative embodiments, handle460 replaces screw 270 (see, e.g., FIG. 1 and FIG. 4). Handle 460includes a cylindrical head 480 that has a diameter or width like thatof head 430 of screw 270. Further, like head 430, head 480 has atextured outer surface or any other outer surface suitable for grippingand manipulating handle 460 by hand. Handle 460 further includes acylindrical threaded shaft 490 configured in a like manner to that ofshaft 440 of screw 270. Also, handle 460 defines a cylindrical channel500 having a diameter or width like that of channel 450 of screw 270(see FIG. 7). However, the lengths of head 480 and channel 500 aresubstantially greater than the lengths of head 430 and channel 450,respectively. The longer head 480 of handle 460 provides an integrallever (or handle) for manipulating alternative embodiments of thepresent invention.

Yet other alternative embodiments include extension member 470 ratherthan screw 270. Member 470 includes a cylindrical threaded shaft 510configured in a like manner to that of shaft 440 of screw 270. Also,member 470 defines a cylindrical channel 520 having a diameter or widthlike that of channel 450 of screw 270 (see FIG. 7). Further, member 470includes a cylindrical head 530 of about the same length as that of head480 of handle 460. However, head 530 is smooth, and has a diameter orwidth only about the same as that of shaft 510. Member 470 provides aneffective extension of tamp 240 through portion 350 of channel 300(without holding tamp 210 together with tamp 240).

FIG. 7 a, FIG. 7 b, FIG. 7 c, and FIG. 7 d show cross-sectional views ofguide rod 280, connecting screw 270, connecting handle 460, andextension member 470, respectively, along lines 7 a-7 a, 7 b-7 b, 7 c-7c, and 7 d-7 d of FIG. 6 a, FIG. 6 b, FIG. 6 c, and FIG. 6 d,respectively.

In operation of exemplary apparatus 200 for impaction grafting a distalfemur, a rasp handle or any other suitable well-known handle type deviceis attached to tamp 210 via post 230 and/or bore 234 in a well-knownmanner. Next, guide rod 280 (alone) is inserted into the femoralmedullary canal and suitably aligned with the longitude of the femur.Allograft is then suitably introduced into a distal part of the canal.Tamp 240 and tamp 210, while held together by screw 270 (or handle 460in alternative embodiments), are slid over rod 280 via opening 390 (tamp240) such that rod 280 extends through portion 400 of channel 380 (oftamp 240) and through channel 450 of screw 270 (or channel 500 of handle460 in alternative embodiments). It should be appreciated that theengagements of tamp 240 and screw 270 (or handle 460 in alternativeembodiments) with rod 280 facilitate alignment of tamp 240 and tamp 210with the longitude of the femur. Then, tamp 240 and tamp 210, still heldtogether by screw 270 (or handle 460 in alternative embodiments), areused to suitably tamp the allograft. The rasp handle merely facilitatesmanipulations of the integrated tamp as desired. After the user becomessatisfied with the resulting distal graft mantle integrity, theintegrated tamp formed by tamp 240 and tamp 210 is once again insertedinto the canal. Screw 270 (or handle 460 in alternative embodiments) andtamp 210 are then removed, but tamp 240 is left positioned in the distalpart of the canal.

Next, with tamp 240 remaining in place, allograft is suitably introducedinto the proximal part of the canal. This allograft is then suitablytamped in the proximal part of the canal by sliding portion 340 ofchannel 300 (of tamp 210) over portion 360 of tamp 240 and, generally,by moving surface 354 (tamp 210) to and fro surface 424 (tamp 240). Itshould be appreciated that the slidable engagement of tamp 210 and tamp240 facilitates proper re-alignment of tamp 210 with the longitude ofthe femur. Here, the rasp handle merely facilitates manipulations oftamp 210 as desired. Additionally, it should be appreciated that inalternative embodiments portion 510 of extension rod 470 may be screwedinto portion 410 of channel 380 (of tamp 240) such that head 530 of rod470 further facilitates proper re-alignment of tamp 210.

Finally, screw 270 (or handle 460 in alternative embodiments) may beinstalled or re-installed through opening 310 (of tamp 210), with shaft440 of screw 270 (or shaft 490 of handle 460 in alternative embodiments)screwed into portion 410 of channel 380 (of tamp 240). It should beappreciated that for embodiments employing member 470, member 470 mustbe removed prior to the installation of screw 270 or handle 460. Screw270 (or handle 460 in alternative embodiments) again secures tamp 210 totamp 240. This allows the integrated impaction grafting tamp to befurther manipulated as desired for trial reductions (mock assemblies inwhich the exemplary generally stem shaped integrated tamp may be fittedinto an acetabulum to test alignments and/or depths of the new canal)and/or for any other suitable work. For trial reductions with theexemplary embodiment, a suitable provisional assembly (mock or trialball) may be attached to tamp 210 via post 230 and bore 234 in a wellknown manner. After the impaction grafting tamping is completed, theintegrated impaction grafting tamp is removed from the canal.

The foregoing description of the invention is illustrative only, and isnot intended to limit the scope of the invention to the precise termsset forth. Further, although the invention has been described in detailwith reference to certain illustrative embodiments, variations andmodifications exist within the scope and spirit of the invention asdescribed and defined in the following claims.

1. A method for impaction grafting an intramedullary canal of a boneincluding a first canal portion and a second canal portion spaced alonga canal axis, the method comprising: moving a first tamp axially withinthe canal to impaction graft the first canal portion; moving a secondtamp, mounted to the first tamp in axial sliding relationship, axiallywithin the canal relative to the first tamp to impaction graft thesecond canal portion; locking the first and second tamps together infixed axial relationship to prevent relative axial movement between thefirst tamp and the second tamp while the first tamp is moved toimpaction graft the first canal portion before impaction grafting thefirst canal portion; and unlocking the first and second tamps to permitrelative axial sliding of the first and second tamps before impactiongrafting the second canal portion.
 2. The method of claim 1 furthercomprising: engaging an extension member with the first tamp such thatthe extension member projects from the first tamp; and engaging thesecond tamp with the extension member in axial sliding relationshipbefore impaction grafting the second canal portion.
 3. The method ofclaim 1 wherein moving the second tamp in axial sliding relationshiprelative to the first tamp comprises sliding an elongated female channeldefined by the second tamp over an elongated male member defined by thefirst tamp, the female channel and male member aligning the tampslongitudinally.
 4. The method of claim 1 further comprising inserting aguide rod into the intramedullary canal and wherein impaction graftingthe first canal portion comprises moving the first and second tampsaxially together over the guide rod and wherein impaction grafting thesecond canal portion comprises leaving the first tamp stationary in thefirst canal portion and moving the second tamp axially relative to thestationary first tamp.
 5. A method for impaction grafting anintramedullary canal of a bone including a first canal portion and asecond canal portion spaced along a canal axis, the method comprising:providing a first tamp having a first tapered portion, wherein the firsttamp has a shape mimicking a femoral hip stem component; moving thefirst tamp axially within the canal to impaction graft the first canalportion; providing a second tamp having a second tapered portion,wherein the second tamp has a shape mimicking a femoral hip stemcomponent, the shape of the second tamp flush with the shape of thefirst tamp about an interface between said tamps and cooperating to forma practically continuous tamping surface when the second tamp abuts thefirst tamp; and moving the second tamp, mounted to the first tamp inaxial sliding relationship, axially within the canal relative to thefirst tamp from a first position in which the second tamp abuts thefirst tamp to impaction graft the second canal portion.
 6. The method ofclaim 5 further comprising: locking the first and second tamps togetherin fixed axial relationship before impaction grafting the first canalportion; and unlocking the first and second tamps to permit relativeaxial sliding of the first and second tamps before impaction graftingthe second canal portion.
 7. The method of claim 5 further comprising:engaging an extension member with the first tamp such that the extensionmember projects from the first tamp; and engaging the second tamp withthe extension member in axial sliding relationship before impactiongrafting the second canal portion.
 8. The method of claim 5 whereinmoving the second tamp in axial sliding relationship relative to thefirst tamp comprises sliding an elongated female channel defined by thesecond tamp over an elongated male member defined by the first tamp, thefemale channel and male member aligning the tamps longitudinally.
 9. Themethod of claim 5 further comprising inserting a guide rod into theintramedullary canal and wherein impaction grafting the first canalportion comprises moving the first and second tamps axially togetherover the guide rod and wherein impaction grafting the second canalportion comprises leaving the first tamp stationary in the first canalportion and moving the second tamp axially relative to the stationaryfirst tamp.
 10. A method for impaction grafting an intramedullary canalof a bone comprising: providing a first tamp; tamping the intramedullarycanal by reciprocally moving the first tamp axially within theintramedullary canal; discontinuing tamping with the first tamp andleaving the first tamp within the intramedullary canal; providing asecond tamp; mounting the second tamp to the first tamp in axial slidingrelationship; tamping the intramedullary canal by reciprocally movingthe second tamp relative to the first tamp within the intramedullarycanal; and locking the first and second tamps together in fixed axialrelationship to prevent relative axial movement between the first tampand the second tamp before said step of tamping the intramedullary canalby reciprocally moving the first tamp axially within the intramedullarycanal, whereby said step of tamping the intramedullary canal byreciprocally moving said first tamp axially within the intramedullarycanal, comprises tamping the intramedullary canal by reciprocally movingboth the first tamp and the second tamp axially within theintramedullary canal, and wherein said step of mounting the second tampto the first tamp in axial sliding relationship comprises the step ofunlocking the second tamp from the first tamp.
 11. The method of claim10, wherein the first tamp has a shape mimicking a femoral hip stemcomponent and the second tamp has a shape mimicking a femoral hip stemcomponent, the shape of the first tamp and the shape of the second tampcooperating to form a practically continuous tamping surface when thesecond tamp abuts the first tamp.